Utilitarianism was originally promulgated by deists, atheists, and agnostics (Jeremy Bentham, James and John Stuart Mill) in England. England at that time was highly religious, but different factions and denominations often disagreed about how to address ethical issues. Utilitarianism was a form of secular ethics that became popular because it gives the illusion of being a simple, straightforward system grounded in practical common sense assumptions about which everyone can agree, a characteristic making it quite appealing as a toolk for practical government policy. Bentham's efforts to quantify happiness so that one could actually calculate "the greatest good for the greatest number" appear to provide a very fair-minded and simple way of evaluating ethical choices. Of course, in reality, goodness and happiness are not as quantifiable as Bentham imagined, but the idea of a simple easy way to be fair to everyone still remains really appealing -- think of how many political platform s are still based on the notion that there really are easy, straightforward sound-bite length solutions to the great problems of the world